Air pollution the world’s largest environmental health risk

Schoolgirl in Bangladesh with an air pollution mask. Photo: Adam Jones/ by-sa

New figures from the WHO link indoor and outdoor air pollution to around 7 million premature deaths a year – more than double previous estimates.

Air pollution is now the world’s largest single environmental health risk, linked to around 7 million deaths in 2012, according to new estimates by the World Health Organization (WHO).

Regionally, South-East Asia has the largest air pollution-related health impacts, with a total of 3.3 million deaths linked to indoor air pollution and 2.6 million deaths related to outdoor air pollution.

After analysing the risk factors and taking into account revisions in methodology, WHO estimates that indoor air pollution was linked to 4.3 million deaths in households cooking over coal, wood and biomass stoves. The new estimate is explained by better information about pollution exposures among the approximately 2.9 billion people that live in homes using wood, coal or dung as their primary cooking fuel, as well as evidence about air pollution’s role in the development of cardiovascular and respiratory diseases, and cancers.

Outdoor air pollution was estimated to cause 3.7 million deaths. Because many people are exposed to both indoor and outdoor air pollution there is an overlap, and mortality attributed to the two sources cannot simply be added together, hence the total estimate of around 7 million deaths.

A breakdown of deaths attributed to specific diseases underlines that the vast majority of air pollution deaths are due to cardiovascular diseases. For outdoor air pollution, the cause of deaths was attributed to: ischaemic heart disease (40%); stroke (40%); chronic obstructive pulmonary disease (COPD) (11%); lung cancer (6%); and acute lower respiratory infections in children (3%).

For indoor air pollution, the causes of deaths were: stroke (34%); ischaemic heart disease (26%); COPD (22%); acute lower respiratory infections in children (12%); and lung cancer (6%).

“The risks from air pollution are now far greater than previously thought or understood, particularly for heart disease and strokes,” said Dr Maria Neira, Director of WHO’s Department for Public Health, Environmental and Social Determinants of Health. “Few risks have a greater impact on global health today than air pollution; the evidence signals the need for concerted action to clean up the air we all breathe.”

Christer Ågren

Source: WHO press release, 25 March 2014.  

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